Dby-kilit



l. F. HIRT.

DRY KILN.

APPLICATION FILED APR.20, 1920.

1,385,451. Patented July 26,1921.

4 SHEETS-SHEET l.

1. F. HIRT.

DRY MLN.

ApPLlCiYl'HNI FILED APR.2| 1920- 1,385,45 1 Patented July 26, 1921.

4 SHEETS-SHEET 2.

J. F. HIRT.

DRY KILN.

APPLlcATloN mso Ammo. 1920.

Patented Ju1y 26, 1921'.

4 sHEErs-sHEET 3.

`1. F; Hm.

DRY KILN.

APPLICATION FILED APR.20. i920.

PATENT OFFICE.

JOSEPH F. HIRT, 0F CHICAGO, ILLINOIS.

DRY-KILN.

specificati on of Letters Patent.

Patented July 26, 1921.

Application filed A'oril 20, 1920. Serial No. 375,212.

To all ely/wm it may concern Be it known that l, Josnrn: H. llrn'r, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Dry-Kilns,of which the following is a specification7 reference being had therein to the accompanying drawing.

The invention relates to drying rooms for lumber, veneers, glue joints in panel cores, lcompleted panels and other wooden articles as well as coatings of varnish, stains, llers, cnamels and paints on articles of furniture, vehicles, interior decoration, etc. However, the invention is particularly adapted for use in connection with drying rooms commonly known as dry kilns.

Apparatus of this character has heretofore been constructed in such manner as would expose the product to be dried directly to the heating units located either horizontally underneath or vertically along the sides or center of the kiln. This invariably has the edect of evaporating the necessary humidity in the immediate vicinity of said heating units and to a lesser degree throughout the kiln. This necessarily being an uneven drying, it is obvious that considerable waste of material is occasioned; therefore it is the principal object of the invention to provide a kiln wherein the material therein will be uniformly dried and at the same time dried quicker than in the common type of kilns now in use, by providing said uniform drying it is obvious thatthe waste of material incident to irregular drying is eliminated.

il further object is to provide a kiln having a drying chamber therein and to provide means whereby a circuit of air,which has been heated before entering' the drying kiln is maintained through the drying kilnfrom the top of the kiln downwardly7 said air as .it enters the drying chamber being supplied with humidity and being thoroughly mixed with the air before entering the drying chamber. Also to provide means whereby fresh air may be added to the recirculating air for supplying oxygen, said fresh air being supplied to the'reoirculating lair at a point so that it"will be thoroughly heat-ed and mixed with the recirculating air before it enters the drying chamber, x

A further object is to provide means whereby the fresh air entering the heating chambers may be controlled in volume and location in the kiln, also to provide means whereby the amount of humidity supplied to the recirculating air may be controlled in amount and in various locations.

A further object is to provide a kiln so constructed that the same may be used as what is known as a box kiln or as what is known as progressive type of kiln.

A further object is to provide ducts of communication between the drying chamber and the heating chamber whereby as the recirculating air passes through the drying chamber said ducts will admit some of the air to the heating chambers which will set up an action which will cause the circulating air in the drying chamber to extend to all parts thereof so that the drying will be uniform.

A further object is to provide curtains adjacent the sides of the entrance passage to the drying chamber, which curtains will causelthe recirculating air to pass downwardly through the material within the drying kiln at a substantially central point thereof and spread outwardly uniformly through the drying chamber.

lV ith the above and other objects in view the invention resides in the combination and arrangement of parts as hereinafter set forth, shown in the drawings, described and claimed, it being understood that changes in the precise embodiment of the invention may be made within the scope of what is claimed without departing from the spirit of the invention.

ln the drawings z- Figure l is a perspectivesectional view, transversely through the kiln.

Fig. 2 is a longitudinal sectional view taken on line 2-2 of Fig. l.

Fig. 8 is a transverse vertical sectional view through the kiln showing a stack of lumber disposed therein.

Fig. l is an end view of the kiln showing a closure therefor.

Fig. 5 is a perspective detail view 'of the deflecti'ng curtains for engaging the top of the material disposed in the drying kiln.

Fig. 6 is a perspective detail view of a portion of the humidity supplyingpipe and controlling means for controllingt 1e amount of humidity supplied to the air.

Fig. 7 is a perspective view of a portion of the humidity supply ypipe showing the 1 Fig. 9 is a sectional view through one of the material engaging curtains.

Fig. 10 is a side elevation of a series of the sections from which the vcurtains are formed.

` Fig. 11 is a'detail view of one of the hu-' Vmidity supplying sections showing the con'- trolling rod connected thereto.

Fig. 12 is a perspective view showing one of the independent dampers for controllingv the amount of fresh air supplied to the heat- Y ing chambers.

Fig. 13 is a perspective view of one of the sliding dampers for controlling the passage of air from the drying chamber to the atmosphere.

Fig. 14 is an enlarged sectional View through a portion of the top of the kiln showing the position of the controlling rods for controlling the humidity7 supply sections and also showing a concaved surface for deiiecting the humidity as it leaves the pipe. l

Referring to the drawings,the numeral 1 designates a kiln and 2 a drying chamber therein. vWithin the side walls 3 'of the drying' chamber 2 are heating chambers 4, in which heating chambers heat-units 5 are disposed, said heating units may be sepaiately controlled from the outside of the kiln so that the amount of heat radiated may be controlled. The side walls 8 of the drying chamber 2 extend upwardly from the floor 6 thereof, Yand are provided with inwardly extending members 7 which' extend toward each other and are spaced from the top 8 of the kiln, thereby forming'passages 9 which merge into each other substantially centrally ofthe dryingchamber as at 10. The obgect of providing the space 10 is.

to provide means whereby as heated air passes upwardly and inwardly through the passages 9, it will pass downwardly into thedrying chamber at a point substantiallycentrally thereof, the purpose of which will presently appear. Disposed above the space 10 is a longitudinally disposed concave detlecting surface 11 against which surface steam is projected from banks of valves 12, which banks of valves are controlled by means of control rods 13, the ends of which are disposed outside of the kiln and form means whereby the amount of humidity supplied to the circulating air may be con# trolled and varied'as desired in various parts of the kiln. Suspended below the humidity pipe 14 is a longitudinally disposed troughr 15, which trough collects and carries off condensation from the steam .and may discharge at any pointoutside of the kiln. The floor 61 is provided with a 'series of passages of communication 16, which passages communicate"l with the lower ends of the heatingV 'chambers 4. Fresh air is admitted to the heating chambers 4 through longitudinally "disposed air ducts 17, preferably disposed beneath the flooring 6 and at both sides of the kiln. The outer ends of the air ducts 17 may communicate with the atmosphere at any point desired, however they preferably communicate withv the atmosphere at the ends'of the kiln. vExtending upwardly from and in communication with the fresh air ducts 17ar'e ducts 18, the upper ends of which discharge into the heating chambers 4, at aipoint substantially two thirds of the way from the bottom of the heating element,

however, it isto be understood that these ducts may coirimunicate with the 'heating chambers atany 'poi-nt desired interposed between the verticalducts 18 and the longitudinal ducts 17 lare slidable dampers 19, ycontrolled by rods 20 which extend to point outside `of the kiln. By means of dampers 19 it will be seen that the amount of air passing from the ducts 17, through the vertical ducts 18 to the hea-ting elements maybe' controlled and varied. Each duct jliumidity may be supplied in varying quantities at Vvarious points, throughA separably controlled mechanisms, the amount of hu-A midity supplied to any particular portion `of the kilnmay be varied as desired.

Extending longitudinally of the kiln and disposed between the floors 6 is a beam 21, the sides of'which are spaced from the adacent sides of the iioo'ri'ng 6. Said spacing of the beam 12 allows the air in its recirculationto pass outwardly to the heating cham! bers 4. The air enters through the ducts 17,'passes upwardly through the ducts 18 and enters theheating chambers 4. The air' is then' heated, and vbeing light rises upwardly and passes inwardly through the lpassages 9,-jthence,v downwardly through the passage 10.V However', immediately before the hotair passes through the passage l() it is supplied with'humidity fromr the humidity pipe 14. After the-hot air is supplied with humidity it passes downwardly through the material in the drying chamber andv enters the passages of communication' 16 tofthe heating chambers 4` where it is again heated.v However as the air passes4 upwardly through the Vheating chamber 4 it will be seen that the ducts 18 will supply fresh air to the recirculating air, thereby providing oxygen. Disposed in the walls 3 are openings 22, which openings 22 communicate with the heating chambers 4. The purpose of the openings 22 is that is has been found that when a recirculation is used for drying purposes, that the heat will not be uniform throughout the drying chamber unless means is provided for causing the recirculating air to be drawn in the direction of the sides of the drying chamber. By providing the openings 22 it will be seen that the heated air in the heating chambers 4 will cause a ycircuit of air to flow through openings 22 thereby causing the recirculating air to be drawn to the sides of the drying chamber so that the air will be uniformly distributed throughout the drying chamber. Extending` outwardly from the bottom of the kiln and preferably disposed beneath the flooring 16 thereof are exhaust ducts 23, the inner ends of which are in communication withl the lower side of the drying chamber as at 24. It will be seen that during the recirculation that a certain amount of the damp air will pass outwardly through the exhaust chiots 23, which ducts preferably discharge as at 25a at points above the kiln proper. The openings 24 are controlled b y means of slidable dampers 26, which dampers are controlled by means of rods 27, which rods have their ends disposed at a point outside of the kiln and are independently controllable, thereby allowing the amount of moist air which naturally falls to lthe bottom of drying chamber to be controlled in its .passage to the atmosphere.

By referring to Fig. 3 it will be seen that lumber has been stacked on trucks and placed in the drying chamber. Lumber when placed in a drying kiln is as a rule uneven in sizes and not closely packed, the layers being spaced from each other by spacing strips as shown at 28 in Fig. 5. It will be seen by referring to Fig. 5 that various sized lumber is shown and that their edges are not in engagement with each other therebv leaving space between the pieces of lumber. When Vthe lumber is in this condition, itwill be seen that the recirculating air,

- `after. being supplied with humidity will pass downwardly centrally and pass between the boards and that by allowing the passage of a portion of the air through the openings 22 the recirculating air will be uniformly distributed in the drying chamber, thereby thoroughly and uniformly drying the lumber throughout its entire length and width. However to compel the recirculating air to pass through` the pile of lumbernlongitudinally disposed curtains 29 are disposed on each side of the opening l0. Curtains 29 may be of any number desired, however, it is preferable. on account of the uneven surface of the top of the stack of lumber that said curtains 29 be formed in sections 80, each section having its lower edge provided with a weight 3l. The weights hold the sections 30 in engagement with the top of the stack of lumber and prevent the air from passing in any direction except downwardly through the lumber. It will also be seen that by providing the spaced curtains deflecting walls are provided which actually contacts with the product in the drying chamber, thereby assuring the passage of the recirculating air through the product within the kiln chamber. From the above it will be seen that a kiln is provided wherein the heated air is circulated with proper velocity, and one wherein a separately controlled amount of fresh air is admitted to the heated recirculating air, thus repl-enishing the recirculating air with fresh air only as it is absorbed by the product being dried. It will also be seen that humidity can be admitted in separately controllable quantities from the various banks of humidifiers throughout the kiln, thereby allowing said humidity to be thoroughly mixed with the recirculating elements, before entering the drying chamber. By providing a kiln having` the fresh air ducts spaced through its length, each separately controlled and having its exhaust ducts spaced throughout its length each separately controlled, it will be seen that all of the drying elements may be controlled to cause and maintain equal proportions of the said drying elements throughout the entire area of the drying chamber' thus providing a compartment or box type kiln, is controllable to meet the severe weather conditions when any one end is exposed, at which time it is necessary to vary the temperature and humidity at the exposed end or; as the heating units are each separately controlled, the fresh air intake ducts are separately controlled, the humidifiers each separately controlled, and the exhaust ducts separately controlled, it will be readily seen that conditions within the drying vchamber proper can be made variable throughout the length of thev kiln, thus causing conditions to exist complying accurately to the conditions maintained in a compartment or box type kiln, and in this case providing what is commonly known as a progressive typ-e kiln.

The invention having been set forth what is claimed as new and useful is l. A kiln having a drying chamber and a heating chamber, means for circulating air through said chambers, means whereby fresh air is admitted to the circulating air at a point where it will pass through the heating chamber before entering` the kiln chamber thereby thoroughly mixing and heatin'g the additionalv fresh air with the recirculating air, before entering the drying chamber, means for supplying humidity to the air before it enters the drying chamber and means for varying the amount of humidity supplied to various portions of the kiln.

2. A kiln having a drying chamber and a heating chamber, means for circulating air through said chambers, means whereby fresh air is admitted to the circulating air in controlled amounts at a point where it will be compelled to pass through the heating chamber before entering the kiln chamber thereby thoroughly mixing and heating the additional fi'esh air with the recirculating air before it enters the drying chamber, means for supplying humidity to the air at various locations before it enters the drying chamber, said humidity being supplied to the air at the top of the chamber, and means whereby the amount of humidity supplied tothe air may be separately controlled in various portions of the kiln from without the kiln.

3. A kiln having a drying chamber and a heating chamber, means for circulating air through said chambers, means whereby fresh air may be admitted to the recirculating air in separately controllable amounts and at points where it will pass through the heat-l ing chamber before entering the drying chamber, means whereby humidity may be supplied to the recirculating air in separately controllable amounts in various portions of the kiln as it enters the drying chamber, means whereby a predetermined amount of the circulating air may be exhausted to the atmosphere from the bottom of the drying chamber and passages of communication between the drying chamber and the heating chamber whereby the circulating air in the drying chamber will be caused to be uniformly distributed in the drying chamber during its recirculating.

4. A kiln comprising a drying chamber and heating chambers disposed to the sides of the drying chamber, ducts for admitting fresh air to the heating chambers, said heating chambers being in communication with the drying chamber substantially in the center at the top thereof and substantially in the center at the bottom thereof, the lower ends of the heating' chambers being in direct communication with the drying chamber at its lower side, heating units disposed in the heating chambers, chiots for supplying fresh air in separately controllable quantities to various locations within the heating chambers where it is mixed and heated, caused to circulate upwardly, inwardly, downwardly through the drying chamber and recirculate through the communications between the lower ends of the heating chambers where it is again heated and supplied with additional fresh air and recirculated, ducts in the side walls of the drying chamber and in limited direct communication with the heating chambers and forming means for causing` the circulating air to be uniformly distributed inl the drying chamber, and separately controllable vducts whereby a predetermined amount ofthe circulating air may be exhausted t0l thefatniosphere from spaced points adjacent the bottom of the dryino' chamber. l v

5. kiln comprisinga drying chamber having heating chambers located at its sides, inwardly extending passages of communication between said heating chambers and the drying chamber atthe upper end thereof, inwardly extending passages of communication between the lower ends of the heating chambers andthe bottom ofY the drying chamber, meansv for admitting fresh air to the heating chambers through separately cont-rolled ducts, whereby fresh air may be applied to the recirculating air, means for recirculating Ythis mixture up between the heating chambers and thence through the drying chamber, downwardly extending longitudinally disposed curtains carried by the upper walls of the drying. chamber and adapted to engage the top of the material in the drying-chamber so asto deflect the recirculating air through the material, said curtains being ,of sufficient length and weighted at their bottoms, thereby compensating for the varying heightsof the products.

6. A kiln comprising a drying chamber having heating chambers located at its sides, inwardly extending passages of communication between said` heating chambers and the drying chambers, inwardly extending passages of communication between the lower ends of the heating chambers and the bottom of the drying chamber, means for admitting fresh air to the heatingy chambers whereby fresh air maybe supplied to the recirculating air as 'it passes through the heating chambers thereby thoroughly mixing the elements before they enter the drying chamber, means for admitting humidity tothe recirculating air before it enters the drying chamber, substantially longitudinally disposed curtains carried by the top wall of the drying chamber and having their lower ends disposed adjacent the top of the material therein for deflecting the recirculating air downwardly throughthematerial, ducts in the side walls of the drying chamber whereby the circulating air will be caused to be uniformly distributed in the drying chamber and passages of communication between the drying chamber and the atmosphere whereby a portion of the circulating air may pass to the atmosphere.

7. A kiln comprising side, top and bottom walls, spaced walls adjacent the side walls and adjacent the top wall, an opening in the top spaced wall substantially centrally thereof, heating elements disposed between the side spaced walls, intake ducts discharging adjacent the heating elements for heating the air before it enters the kiln chamber, and means whereby the air will recirculate between the spaced walls and the kiln chamber and exit from the bottom of the kiln chamber substantially centrally thereof.

8. The combination with a kiln having a drying chamber therein, of inverted L- shaped chambers located at the sides of the drying chamber, heating elements in the substantially vertical portions of said heating chambers, `duct means for supplying fresh air to said substantially vertical portions, the horizontal portions of said L- shaped chambers extending toward each other and disposed over the drying chamber and having their ends spaced apart, thereby providing an entrance passage to the drying chamber substantially centrally thereof, controllable means for admitting humidity to the air as it enters the drying chamber, and duct means whereby the recirculating air will leave the drying chamber at its bottom and substantially centrally thereof.

9. In a kilnof the character described comprising means whereby a controlled supply of fresh air is admitted at a point within the heating chamber, the air heated and recirculated through a drying chamber and supplied with fresh air during its circuit at a point within the heating chamber, said recirculating air entering the upper end of the drying chamber substantially centrally thereof and leaving the lower end of the drying chamber at a point substantially centrally thereof.

10. A kiln having a drying chamber and a heating chamber, means for circulating air through said chambers, means whereby the circulating air will enter the drying chamber substantially centrally at its top and eXit from said drying chamber substantially centrally at its bottom, duct means whereby fresh air may be admitted to the heating chamber through spaced ducts, and means for separately controlling the inflow of fresh air from each duct, thereby admitting additional fresh air to the circulating air in controllable quantities as desired.

ll. A kiln having a drying chamber and heating chambers, means for circulating air through said chambers, means whereby fresh air may be admitted to the circulating air at points where it will pass through the heating chambers before entering the drying chamber, said heating chambers being located on each side of the drying chamber, the upper and lower ends of the heating chambers being in communication with the drying chamber at points substantially centrally thereof, and ducts in the side walls of the drying chamber adjacent their lower ends and in direct communication with the heating chambers.

In testimony whereof I hereunto afHX my signature.

JOSEPH F. HIRT. 

